In the 2011 action-thriller "Unknown", scientists are persecuted by the biotech industry because they plan the open release of a drought- and pest-resistant strain of maize that could help eradicate world hunger.

A decades-long push to require the labelling of foods containing genetically modified ingredients in the United States received a significant boost Wednesday, when bipartisan bills on the issue were simultaneously proposed in the House and Senate.

Food safety advocates, environmentalists and health professionals here are engaging in a fervent last-minute campaign to highlight a controversial legislative amendment they say would gut the ability of both the judiciary and the federal government to regulate genetically modified agricultural products.

Environmental activists are cautiously optimistic that a call by a court-appointed technical committee for a ten-year moratorium on open field trials of genetically modified (GM) crops will shelve plans to introduce bio-engineered foods in this largely agricultural country.

In 1994, genetically modified produce, in the form of tomatoes, first appeared in grocery stores in the United States. Numerous other types of produce have been genetically modified since, and consuming them has become common practise. But because the phenomenon is so recent, the long-term effects of eating such foods remain unknown.

Biodiversity and small and medium farms are threatened in Mexico by the looming approval of a reform of the law on plant varieties that will extend patent rights over seeds, activists and experts warn.

Catalina Salvador, an 87-year-old peasant farmer who grows pumpkins, beans, and above all corn on her small plot of land, was one of the opponents of transgenic crops who took part in the traditional corn festival in San Juan Ixtenco in the central Mexican state of Tlaxcala.

Researchers in Argentina have isolated a sunflower gene and implanted it into corn, wheat and soybean seeds to make them more resistant to drought and soil salinity, problems increasingly faced by this South American agricultural powerhouse as a result of global warming.

Critics complain that a genetically modified bean developed in Brazil, resistant to one of the country's most damaging agricultural pests, was approved without enough debate or guarantees that the crop will not affect human health or the environment.